Hydroinformatics is a sociotechnical endeavour, which is to say that it deals with social processes that cannot proceed without the provision of appropriate technologies and technologies that cannot succeed without the introduction of appropriate social arrangements. In particular, the introduction of decision-support systems for very large numbers of persons in so-called ‘third-world ’ societies, such as farmers, aquaculturalists and medical help providers, must be prepared by studies of the social and the technical aspects inseparably. Such decision-support systems have typically to provide advice on water-related issues to a very wide variety of individuals, families and other social groups, so that the advice that is provided must be the most appropriate to the specific individual, family or other social group to which it is given. This kind of ‘personalised ’ or ‘customised ’ service is identified as being essential to what is introduced here as a ‘knowledge-intensive agriculture’. The need to customise knowledge in such a context in turn necessitates that each such individual, family or other kind of social group must be accurately characterised by an ‘end-user profile ’ in such a way that the advice that is given may be appropriate. The construction of these end-user profiles is itself a time-consuming task that calls for special skills and it is essential to the integrated sociotechnical